Write some Software

I need a script or app that checks a list of about 20 URLs once a day to see if any HTML has been changed since it checked on the previous day. If something has been changed, I need the app to send an email with an HTML file that adds a distinctive border or highlight (like a red border) around the elements that have been changed (such as the div container where the content is located on the page) to a specific email address. The recipient would then, ideally, be able to open the HTML file and see highlighted the things that have been changed on that page. The primary goal of this is to notify the recipient of any changes (usually minor changes to text or images). Ideally, this app is something that could be uploaded to our HubSpot portal and run from there, but there aren't many server-side functionalities available there so this is only viable if this is an html or javascript file of some kind or another file that doesn't require server-side work. If it can't work that way, then it needs to be able to work on the [login to view URL] server. I can provide you with the login credentials for WebFaction, but I'd need you to install it. Please make sure that your solution would be able to work either as a file uploaded to HubSpot (ideal) or on WebFaction. The list of URLs to check will probably not change frequently, but will probably change on occasion. Ideally, we can make the changes ourselves either through an interface or if you can markup where in the code you're listing the URLs. Feel free to let me know if you have any questions at all! I'm happy to clarify anything. I'm also open to feedback on other ways to accomplish the primary goal of email notifying of changes to a URL.